The NASA Curiosity rover that was thought to bring only cameras, sensors, and scientific equipment when it traveled to Mars in August 2012 may have brought along dozens of species of bacteria that originated on Earth, according to a new study.

A study conducted by the American Society for Microbiology and
published in the Nature science journal revealed that 377
strains of bacteria may have survived the sterilization process
that the Curiosity rover endured before it was launched in an
attempt to avoid contaminating the red planet.

It was less of a surprise for scientists that the bacteria
survived the cleaning process than the revelation about the
conditions they went through. The microbes in question endured
near-freezing temperatures and intense damage caused by ultra-C
radiation, thought to be the most harmful type of radiation.

“Although studies are constantly expanding our knowledge
about life in extreme environments, it is still unclear whether
organisms from Earth can survive and grow in a Martian
environment where there is intense radiation, high oxidation
potential, extreme desiccation, and limited nutrients,”
microbiologist Stephanie Smith of the University of Idaho in
Moscow and lead author of the study wrote in the study’s abstract.

“Knowing if microorganisms survive in conditions simulating
those on the Martian surface is paramount to addressing whether
these microorganisms could pose a risk to future challenging
planetary protection missions.”

Whether the bacteria spread to the Mars surface is unknown,
although the very possibility has already made scientists
concerned about unnaturally spreading life from earth to Mars.

There is already a United Nations Outer Space Treaty that aims to
regulate how the increasingly advanced space programs from the
international community explore the unknown. The parameters were
first agreed upon in 1966 and they include, among others, the
stipulation that “States shall be liable for damage caused by
their space objects; and shall avoid harmful contamination of
space and celestial bodies.”

The limits vary depending on where the spacecraft lands. Mars,
Europa, and other bodies that could potentially nurture life have
a relatively strict standard of 300 bacterial spores per square
meter. The goal is to keep the odds of contamination Mars (and
others) at less than 1 in 10,000.

“Up to 300,000 spores are allowed on the exposed surfaces of
the landed spacecraft. That many spores would fit on the head of
a large pin,” said Laura Newlin, an engineer at NASA’s Jet Propulsion Laboratory in
California. “Currently our total spore count on the
surface…is comfortably under 200,000, so we’re below the
allowable level.”

The announcement comes at a time when another team of researchers
published an unrelated study revealing that methanogens, the
oldest organisms on earth, could be the perfect candidate to
foster Martian life. The University of Arkansas Fayetteville
study determined that, because methanogens are non-photosynthetic
and capable of living without oxygen, they are capable of living
underground on Mars.

“The surface temperature of Mars varies widely, often ranging
between minus 90 degrees Celsius and 27 degrees Celsius over one
Martian day,” Rebecca Mickol, a doctoral student of space
and planetary sciences, told Science Daily. “If any life were to exist
on Mars right now, it would have to at least survive that
temperature range. The survival of these two methanogen species,
exposed to long-term freeze thaw cycles, suggests methanogens
could potentially inhabit the future of Mars.”